Contacts for electric circuit breakers, switches, connecters and the like



Patented Feb. 25, 1936 UNITED STATES PATENT OFFICE George EthelbertWhitehead, Rhiwbina, near Cardiff, South Wales Application December 19,1933, Serial No. 703,108 In Great Britain January 6, 1933 6 Claims.

This invention relates to plug and socket type contacts of electricalcircuit breakers, switches, connecters and the like and for its mainobject aims to provide an improved form of socket con- 5 tact and foranother object, seeks to produce improved forms of the main andauxiliary contacts `claimed in my earlier application Serial No.632,073. f

To enable the invention to be clearly understood, it will now bedescribed with reference to the accompanying drawing in Which Fig. l isa sectional elevation of the socket contact in accordance with theinvention and; Fig, 2 is an enenlarged plan View of part of the socketcontact shown in Fig. 1, whilst Fig. 3 is asectional elevation of thecontacts of the circuit breaker as claimed in my earlier applicationSerial No. 632,073 aforesaid, with the present invention applied to boththe main current carrying contact members.

According to the present invention, a socket contact member has itsfemale contact surface formed by the inner edges of a plurality ofcircularly stacked lamin retained in a carrier in such manner that saidsurface is resiliently expansible. Conveniently, said contact comprisesa large number of similar bent strips, preferably of copper, stacked sothat at their outer ends .,O they bear against an outer ring or housingso as to be self-retaining in the radial direction, means being providedto retain the strips against longitudinal displacement only. If desired,each two adjacent lamina may have between them a phos- 35 phor bronze orsteel backing spring bent to the same shape but preferably of slightlyless length than the copper strips.

According to a further feature of the invention, the main currentcarrying contacts of 40 switches or circuit breakers as claimed in theaforesaid application are constituted respectively by an enlargedportion of the plug contact and by an annularly laminated contact ashereinbefore set forth, housed in an enlarged down- 45 wardly extendedmouth ring of the arcing chamber or housing of the arcing contacts.Preferably, the enlarged portion of the plug contact has longitudinalbores to permit oil or other fluid to flow freely at all times into thearcing chamber 50 or housing. Preferably also the main current carryingcontacts are arranged to separate before the arcing contacts separate.

Referring rst to Figs. 1 and 2 of the drawing, the socket contactcomprises the ring or housing 55 |0| having a stem portion |02 forconnection to (Cl. 20D-166) any current conductor as desired. Thehousing is provided with an inner shoulder |03 between which and aretaining ring |04 are held the circularly stacked lamin |05. The end ofthe plug contact is indicated at |06. 5

The lamin are preferably all bent to the same shape shown on an enlargedscale in Fig. 2 so that the outer edges bear against the innercylindrical wall of the housing |0| at an angle to the radii whilst theinner ends are substantially radial as shown at |01. If desired, such asin large contacts, each lamina |05 may be separated from the next by aphosphor bronze or even steel lamina |08 which has the same generalshape but is of slightly shorter length than are the lamina: |05 whichare preferably of copper.

Referring next to Fig. 3, the latter is similar to Fig. 2 of myaforesaid earlier application.

It will be seen from Fig. 3 that the arcing chamber or housing 2| has adownwardly extend- 20 ing mouth ring portion |0|' of larger diameterthan is shown in the aforesaid earlier application, this portion havinga retaining ring |04' and constituting the housing as shown in Figs. 125 and 2 of the drawing herewith for the laminated annular main currentcarrying contact |05 with which co-operates a portion |09 of largerdiameter than the moving contact, the end 5 of which latter co-operateswith the housed contacts 3. The arcing plug 5 may be screwed into a boreI0 in the enlarged plug portion |09 and the latter is preferablyprovided with a plurality, for example four, of longitudinal boresthrough which oil can pass at all times, as indicated by the chain linearrow, into the housing 2| and out through the gas escape openings 22therein.

In Fig. 3 the moving Contact member is shown in the closed position infull lines whilst in dotted lines it is shown in the position which itoccupies at the instant of commencement of arcing and it will be seenthat at this instant there is a relatively large annular opening throughwhich oil can flow around the plug member |09 as indi- 45 cated by thetwo full line arrows.

It will be understood that various minor modications may be made withinthe scope of the invention.

I claim:

1. An electrical socket contact member, comprising an annular housingand held therein an annulus of closely packed thin flexible lamin eachof which is engageable with the one on each side of it along a pluralityof longitudinal lines of contact of which at least one line is adjacentthe inner edge of the lamina thereby providing a substantially solidWall adjacent to said inner edge and forming a socket member with aneffectively continuous resiliently expansible laminated brush form offemale contact surface.

2. An electrical socket contact member, comprising an annular housingand held therein an annulus of closely packed thin flexible lamin eachof which is engageable with the one on each side of it along apluralityrof longitudinal lines of contact of which at least one line isadjacent the inner edge of the lamina thereby providing a substantiallysolid Wall adjacent to said inner edge and forming a socket member withan effectively continuous resiliently expansible laminated brush form offemale contact surface, alternate lamina: being of stiier material andof only slightly shorter radial length than the other lamin.

3. An electrical socket contact member, comprising an annular housingand held therein an annulus of closely packed thin iiexible lamin eachof which is engageable with the one on each side of it along a pluralityof longitudinal lines of contact of which at least one line is adjacentthe inner edge of the lamina thereby providing a substantially solidwall adjacent to said inner edge and forming a socket member with aneiectively continuous resiliently expansible laminated brush form offemale contact surface, all said lamin having a similar generalcurvature as distinct from angularity.

4. An electrical socket contact member, comprising an annular housingand held therein an annulus of closely packed thin exible lamin each ofwhich is engageable With the one on each side of it along a plurality oflongitudinal lines of contact of which at least one line is adjacent theinner edge of the lamina thereby providing a substantially solid Walladjacent to said inner edge and forming a socket member With aneiectively continuous resiliently expansible laminated brush form offemale contact surface, all said lamina: Yhaving a similar generalcurvature as distinct from angularity and alternate laminas being ofstiier material and of only slightly shorter radial in the oppositedirection at the ends, each of which lamin is engageable with the one oneach side of it along a plurality of longitudinal lines of contact ofwhich at least one line is adjacent the inner edge of the lamina therebyproviding a sub- V-stantially solid Wall adjacent to said inner edge andforming a socket member With an effectively continuous resilientlyexpansible laminated brush form of female contact surface.

6. An electrical circuit breaker having a tubular metal housing, a pairof relatively longitudinally movable cooperating contacts of Which oneis of elongated plug form whilst the other contact is located in saidtubular metal housing with its contact surface disposed between the endsof said housing and protruding inwardly from the inner Wall surfacethereof, a mouth ring forming part of said housing and through whichsaid elongated plug contact enters to engage only said contact withinsaid housing, said housing comparatively closely surrounding theengaging contact and being provided with an opening for the free escapeof the arc gases, an enlarged extension of said mouth ring, anenlargement on said plug contact, and an annulus of closely packed thinflexible lamin held in the mouth ring each of which lamn is engageableWith the one on each side of it along a plurality of longitudinal linesof contact of which at least one line is adjacent the inner edge of thelamin thereby providing a substantially solid Wall adjacent to saidinner edge and forming a socket member with an effectively continuousresiliently expansible laminated brush form of female contact surfacewhich is adapted to be engaged by the enlargement on said plug contact,said enlargement constituting the main current carrying plug member.

GEORGE ETHELBERT WHITEHEAD.

